People waited to deposit their old high-denomination currency notes on Saturday outside a bank in Guwahati, India. Prime Minister Narendra Modi said last week that the public could get new large notes at banks, but customers have faced waits of many hours.CreditCreditReuters

MUMBAI, India — Voice quivering, Prime Minister Narendra Modi on Sunday dramatically countered criticism of his surprise ban on most currency in circulation in India, a bold attack on corruption that crippled business at stores and markets around the country as millions scrambled for cash to meet even basic needs.

“My fellow citizens, I left my home, my family, all that I left for my country,” Mr. Modi said, pausing to compose himself as he raised his left arm skyward and pounded his chest.

“Did you vote for me to abolish corruption?” he thundered, a rhetorical question from a man who led his party to victory two years ago with promises to fight corruption and promote economic development. “If you asked me, should I do it or not?” he bellowed.

Mr. Modi delivered the speech at a groundbreaking ceremony for a new airport in Goa. Known for its beautiful beaches, Goa is one of five Indian states with local elections in the coming months, and Mr. Modi’s speech seemed aimed in part at using his anticorruption move for political gain.

But for the most part, it was a response to the biting criticism from opposition leaders who argued that poor Indians were struggling to make ends meet as a result of his ban on the existing 500-rupee and 1,000-rupee notes, worth $7.50 and $15. Mr. Modi said last week that the public could get new large currency notes at banks and smaller denominations at A.T.M.s, but people have faced waits of many hours at banks that at times have run out of cash, and many bank machines are not working or have run out of money.

Mr. Modi appealed to the public to bear the inconvenience for the promise of a nation free of “black money” — unaccounted-for cash on which taxes have not been paid.

Even as people jostled in lines that continued to be several hours long over the weekend, many interviewed seemed willing to accept monumental inconveniences if Mr. Modi’s policy would reduce their country’s endemic corruption.

Tanvir Sheikh, 38, a hairdresser to Mumbai’s elite, told of suffering personally and professionally since Mr. Modi’s ban went into effect. Mr. Sheikh had to cut short his family’s Goa vacation and return to Mumbai on Thursday because he was carrying cash that was no longer usable and his hotel did not take credit or debit cards.

He spent five hours in line at his bank branch here, only to reach a teller who had run out of the new notes. And on Sunday, when he usually has appointments all afternoon for haircuts and color treatments at Beau Monde salon in the neighborhood of Colaba, only one client showed up, the rest lacking the cash to pay.

His family was surviving on 1,500 rupees in small-denomination notes that he fished out of his daughter’s piggy bank, he said.

“I am willing to handle all of this if this will really reduce corruption,” Mr. Sheikh said as he held a blow-dryer to his sole client’s hair in the otherwise empty salon.

A Mumbai taxi driver, Girja Prasad Goswami, 48, said his daily earnings had been cut in half, to 300 rupees, since Mr. Modi’s ban went into effect. He was not sure how he would send money to his wife and three daughters in his home village in Uttar Pradesh if business did not pick up. Yet he said, “If it’s going to help the nation, I am willing to continue.”

In banning the two largest currency notes on Tuesday, Mr. Modi aimed to reduce the use of unaccounted-for cash in India, where experts have estimated that one-third of transactions are made this way. With the sudden ban, Mr. Modi rendered vast caches of unaccounted-for cash useless.

Mr. Modi, in his Sunday speech, asked the public for 50 days of forbearance for a transition to new bills of 500 and 2,000 rupees. Complicating that transition is the fact that many of the country’s approximately 200,000 A.T.M.s are not working. Those that are working are quickly running out of 100-rupee notes, and none of the machines are capable of dispensing the new 2,000-rupee notes, which are a different size from the previous notes.

The finance minister, Arun Jaitley, said recalibrating the A.T.M.s to dispense the new notes would take as long as three more weeks. The machines were not recalibrated before last week’s edict; by keeping the move a secret, officials prevented big holders of unaccounted-for money from outwitting the ban.

The Finance Ministry said on Sunday that Indians had deposited about $45 billion in banned currency notes since the policy began. Banks and A.T.M.s had given out $7.5 billion in new currency notes during that time, the ministry said.

At a State Bank of India branch in the New Ashok Nagar neighborhood in New Delhi, about 300 people had been waiting in line for two hours when the bank opened at 10 a.m. Sunday. But word immediately spread that the bank’s computer server was not working and that no business could take place until it came back online.

As Murli Manohar Mehta, the bank manager, frantically dialed his technology engineers, the crowd grew larger and angrier and began shouting slogans. The lone security guard cowered until two police officers showed up to help.

“We are trying hard to serve the people,” Mr. Mehta said in an interview. “But now I am helpless. What can I do if the server is not operating?”

A day earlier, the crowd grew so angry that it broke the steel grille on the bank door, he said. None of the several A.T.M.s within walking distance of the bank were dispensing cash Sunday morning.

Sunil Kashyap, 35, running an electrical store in East Delhi, said his sales had fallen 50 percent. The problem was that nobody had cash to pay for purchases, he said. His customers kept trying to make him accept the banned notes, but he was refusing, he said, adding, “What will I do with those notes?”

Still, Mr. Kashyap supported Mr. Modi’s ban, saying: “It is like a bitter pill. It will give relief in the long term.”

Near Delhi’s celebrated Khan Market, most of those who were angry about the ban said they were suffering for no reason.

In line at an HSBC bank machine, two students offered scathing words about the ban’s effect on poorer Indians, who were missing work because they were standing in line at A.T.M.s. “The actual black money,” said Muskan Sandhu, 21, a literature student, “is stashed away in Swiss bank accounts.”

Geeta Anand reported from Mumbai, and Hari Kumar from New Delhi. Ellen Barry contributed reporting from New Delhi.

A version of this article appears in print on , on Page A10 of the New York edition with the headline: India’s Leader Delivers Emotional Defense of Currency Move. Order Reprints | Today’s Paper | Subscribe